<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .tringle{
             width: 0px;
            height: 0;
            border:100px solid red;
            /* border-bottom-width: 0; */
            border-left-color: green;
            border-right-color:blue ;
            margin-bottom: 50px;

        }
        .box{
            width: 300px;
            height: 100px;
            background-color: rgb(228, 241, 213);
            border-radius: 10px;
            position: relative;
        }
        .box::before{
            content: '';
            display: block;
            width: 0;
            border:20px solid rgb(228, 241, 213);
            border-top-width: 0;
            border-left-color: transparent;
            border-right-color:transparent ;
            position: absolute;
            top:-20px;
            left:10px;
        }
        .box:active{
            cursor: text;
        }
    </style>
</head>
<body>
    <div class="tringle"></div>
   
    <div class="box"></div>
</body>
</html>